This invention relates to protective coatings and, more particularly, to ceramic composite protective coatings and methods of manufacture.
Components, such as aerospace components, typically utilize protective coatings to protect the component from detrimental effects caused by high temperatures and corrosive or erosive conditions. For example, aerospace components typically include one or more coating layers that resist oxidation of the underlying component to thereby enhance durability or maintain efficient operation of the component.
Types of protective coatings that are used to protect ceramic components are silica and silica-containing glasses. Although effective at relatively low temperatures, the silica and silica-containing glasses may soften or melt if the temperature exceeds 1200° F. (650° C.) and become less effective as protective coatings. Alternatively, the protective coating may be composed of a refractory silicide in a glassy matrix. However, while silicide containing layers may improve the temperature capability of the coating, they do not perform well at temperatures exceeding 3000° F. (1650° C.). Also, under certain situations such as high Mach environments, glass-based coatings could erode off the component surface, thereby being non-protective, and thus increasing the likelihood of premature failure of the component.
Accordingly, there is a need for a protective coating having enhanced oxidation resistance at elevated temperatures and a method for manufacturing the protective coating. This invention addresses those needs while avoiding the shortcomings and drawbacks of the prior art.